The daily precipitation data from 73 meteorological stations covering the areas of middle-lower reaches of Yangtze River from 1961 to 2012 were used to analyze the characteristics and distribution of rainstorm intensity and the maximal consecutive rainfall. The rainstorm intensity at different recurrence intervals of rainstorm such as 100-year and 50-year was obtained. Based on these spatial analyses and the spatial data such as digital elevation model (DEM), land use and soil type, the advanced WetSpa Extension model was used to simulate the runoff yield and concentration into the trunk stream of Yangtze River under different rainstorm intensities and consecutive rainfall scenarios. And then, the potential submerged areas and the spatial distributions of rainstorm flooding in croplands, wetlands and lakes were mapped using the GIS methods. The results showed that the regions along the Yangtze River belonging to Hubei, Anhui, Jiangxi and Jiangsu provinces were the highest occurrence areas of rainstorm. The rainstorm days and the maximal daily precipitation increased insignificantly in the past 50 years. The rainstorm intensities of 100-year, 50-year and 10-year recurrence intervals were 220, 190 and 120 mm·d^-1 respectively, and the maximum consecutive rainfall in the study area was more than 400 mm. Consequently, the areas submerged in 0.5-1.5 m by flooding under the four extreme rainstorm scenarios were

4.3×10⁴, 2.6×10⁴, 1.6×10⁴ and 6.7×10⁴ km², and the submerged cropland accounted for 83.7%, 74.1%, 65.1% and 88.1%, respectively. These results and the submerged area maps can help to prevent storm flooding, analyze the flood risk and evaluate the disaster losses.